Continuous and semi-continuous methods of semi-solid electrode and battery manufacturing

ABSTRACT

Embodiments described herein relate generally to systems and methods for continuously and/or semi-continuously manufacturing semi-solid electrodes and batteries incorporating semi-solid electrodes. In some embodiments, the process of manufacturing a semi-solid electrode includes continuously dispensing a semi-solid electrode slurry onto a current collector, separating the semi-solid electrode slurry into discrete portions, and cutting the current collector to form a finished electrode.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to and the benefit of U.S. ProvisionalPatent Application No. 62/695,483 entitled “Continuous andSemi-Continuous Methods of Semi-Solid Electrode and BatteryManufacturing,” filed Jul. 9, 2018, the disclosure of which is herebyincorporated by reference in its entirety.

TECHNICAL FIELD

Embodiments described herein relate generally to systems and methods forcontinuously and/or semi-continuously manufacturing semi-solidelectrodes and batteries incorporating semi-solid electrodes.

BACKGROUND

Battery manufacturing methods typically include coating a conductivesubstrate (i.e., a current collector) with a slurry that includes anactive material, a conductive additive, and a binding agent dissolved ordispersed in a solvent. After the slurry is coated onto the metallicsubstrate, the slurry is dried (e.g., by evaporating the solvent) andcalendered to a specified thickness. The manufacture of batteryelectrodes can also commonly include material mixing, casting,calendering, drying, slitting, and working (bending, rolling, etc.)according to the battery architecture being built. Because the electrodeis manipulated during assembly, and to ensure conductive networks are inplace, all components are compressed into a cohesive assembly, forexample, by use of the binding agent. However, binding agents themselvesoccupy space, can add processing complexity, and can impede ionic andelectronic conductivity. Thus, there is a need for improvements inelectrochemical cells (e.g., batteries) and the manufacture ofelectrochemical cells, such as eliminating components of theelectrochemical cell and/or providing reduced packaging for theelectrochemical cell, while maintaining the same energy storagecapabilities.

SUMMARY

Embodiments described herein relate generally to systems and methods forcontinuously and/or semi-continuously manufacturing semi-solidelectrodes and batteries incorporating semi-solid electrodes. In someembodiments, the process of manufacturing a semi-solid electrodeincludes continuously dispensing a semi-solid electrode slurry onto acurrent collector, separating the semi-solid electrode slurry intodiscrete portions, and cutting the current collector to form a finishedelectrode.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates steps of a process for manufacturing an electrodeand, optionally, an electrochemical cell, according to an embodiment.

FIG. 2 illustrates a dispensing mechanism, according to an embodiment.

FIG. 3 illustrates a dispensing mechanism, according to an embodiment.

FIG. 4 illustrates a dispensing mechanism, according to an embodiment.

FIG. 5 illustrates a process for manufacturing an electrode, accordingto an embodiment.

FIG. 6A is a photograph of a semi-solid electrode slurry deposited ontoa moving current collector having a portion of the current collectortucked between two plates, according to an embodiment.

FIG. 6B is a photograph of the current collector of FIG. 3A after movingthe two plates apart to uncover the tucked portion of the currentcollector, according to an embodiment.

FIG. 7 is a schematic diagram of a system for semi-continuous orcontinuous manufacture of a semi-solid electrode, according to anembodiment.

FIG. 8 is a schematic diagram of a system for semi-continuous orcontinuous manufacture of a semi-solid electrode, according to anembodiment.

FIG. 9 is a schematic diagram of a system for semi-continuous orcontinuous manufacture of a semi-solid electrode, according to anembodiment.

FIG. 10 is a schematic diagram of a system for semi-continuous orcontinuous manufacture of a semi-solid electrode, according to anembodiment.

FIG. 11 is a schematic diagram of a system for semi-continuous orcontinuous manufacture of a semi-solid electrode, according to anembodiment.

FIGS. 12A-12C illustrate steps of a process to manufacture anelectrochemical cell, according to an embodiment.

DETAILED DESCRIPTION

Embodiments described herein relate generally to systems and methods forcontinuously and/or semi-continuously manufacturing semi-solidelectrodes and batteries incorporating semi-solid electrodes.Embodiments described herein relate generally to methods formanufacturing semi-solid electrodes include disposing a semi-solidelectrode material onto a current collector. In some embodiments, themethod can include continuously dispensing a semi-solid electrode slurryonto a current collector, separating the semi-solid electrode slurryinto discrete portions, and cutting the current collector to form afinished electrode.

Conventional electrodes and conventional electrochemical cells aretypically prepared by coating a discrete portion of metal foil substratewith a thin (e.g., about 10 μm to about 200 μm) wet slurry that issubsequently dried and calendered to a desired thickness. The slurrycomponents in this method are typically active materials, conductiveadditives, a binding agent, and a solvent (e.g., commonlyN-Methylpyrrolidone (NMP)). When the solvent is evaporated (in a dryingoven covering the conveying line), the binder converts to a “glue” thatholds all of the solid particles together in a matrix bound to thesubstrate. It is common for electrodes to be coated with the samematerials on both sides of the substrate.

There are two common battery design approaches, (1) wound, and (2)stacked. In wound battery designs, electrode sheets can be cut to targetdimensions, and then, with a separator placed in between, wound into aspiral or jelly-roll, then infiltrated with electrolyte and suitablypackaged (typically in a cylindrical or rectangular metal can) to affordcontainment and electrical connections. In stacked battery designs,electrode sheets can also be cut to target dimension, but are thenstacked on top of one another with separators placed in between. Thus, astacked cell is composed of physically discrete electrode sheets ratherthan continuous electrodes (i.e., in anode/cathode pairs) in the case ofwound cells. The stacked assembly can then be infiltrated withelectrolyte and commonly packaged in either a pouch/bag, a plastic box,or a metal can, which can each also be referred to as a cell or batterycasing as described herein.

In conventional pouch packaging, the pouch can perform severalfunctions. One such function is to provide a hermetic isolation ofbattery materials from the environment. Thus, the pouch can serve toavoid leakage of hazardous materials such as electrolyte solvents and/orcorrosive salts to the ambient environment, and can prevent water and/oroxygen infiltration into the cell. Other functions of the pouch caninclude, for example, compressive packaging of the internal layers,voltage isolation for safety and handling, and mechanical protection ofthe battery assembly.

Typical pouch materials can include laminates (e.g., multi-layersheets), formed into, for example, two or three solid film-like layersand bound together by adhesive. The word “laminate” as used herein canalso refer to layers of material that are not chemically adhered to oneanother. For example, the layers can be in areal contact with each otherand coupled using other coupling methods, such as, for example, heatsealing. The inner layer can be, for example, a plastic layer, such as,for example, a cast polypropylene (CPP). The next or second layer can bea metal foil layer, such as, for example, aluminum or aluminum alloy. Insome pouch configurations, there can be an additional layer(s). Theadditional layer can be, for example, a protective coating, formed with,for example, a plastic, such as nylon. The metal foil can provide thefunction of hermeticity, being much less permeable to certain compounds,especially water, than plastics. The inner plastic layer can bethermally bondable to itself, which is the convention regarding pouchclosure and admission of electrical pass-throughs. In pouch closure, ifthe inner layers (e.g. CPP) of two pieces of pouch laminate are broughtinto physical contact, and heat is applied, the layers will melt andfuse, creating a robust seal if the processing conditions (e.g., power,temperature, duration) are chosen appropriately. For example, when thesealing is done in a closed loop, an interior volume can be formed thatis isolated from the ambient or exterior environment.

Some known electrochemical cells (e.g., batteries) can include a varietyof shapes and/or sizes, can be based on a wide variety of enablingmaterials and internal architectures, can be either passive or activelycontrolled, can be rechargeable or not, and/or can share certain commonfeatures that can allow them to convert chemical energy to electricalenergy. Some known batteries can include a first electrode having a highelectrochemical potential and a second electrode having a lowerelectrochemical potential relative to the first electrode. Eachelectrode can include an active material that participates in a chemicalreaction and/or physico-chemical transformation during discharge byvirtue of a favored thermodynamic change of material states, which canresult in the flow of electrical current when a switch is closed. Insome cases, for charge transfer to occur, two distinct conductivenetworks can allow the anode and cathode to be electrically connected. Aseparator can be used to provide isolation of the anode and cathode suchthat only ions are able to pass through it, and to prevent shortcircuiting.

The manufacture of battery electrodes can be a complex and capitalintensive process, and can commonly include material mixing, casting,calendering, drying, slitting, and working (bending, rolling, etc.)according to the battery architecture being built. Because the electrodeis manipulated during assembly, and to ensure conductive networks are inplace, all components are compressed into a cohesive assembly, forexample, by use of a binding agent. However, binding agents themselvesoccupy space, can add processing complexity, and can impede ionic andelectronic conductivity.

As used in this specification, the singular forms “a,” “an,” and “the”include plural referents unless the context clearly dictates otherwise.Thus, for example, the term “a member” is intended to mean a singlemember or a combination of members, “a material” is intended to mean oneor more materials, or a combination thereof.

The term “substantially” when used in connection with “cylindrical,”“linear,” and/or other geometric relationships is intended to conveythat the structure so defined is nominally cylindrical, linear or thelike. As one example, a portion of a support member that is described asbeing “substantially linear” is intended to convey that, althoughlinearity of the portion is desirable, some non-linearity can occur in a“substantially linear” portion. Such non-linearity can result frommanufacturing tolerances, or other practical considerations (such as,for example, the pressure or force applied to the support member). Thus,a geometric construction modified by the term “substantially” includessuch geometric properties within a tolerance of plus or minus 5% of thestated geometric construction. For example, a “substantially linear”portion is a portion that defines an axis or center line that is withinplus or minus 5% of being linear.

As used herein, the term “set” and “plurality” can refer to multiplefeatures or a singular feature with multiple parts. For example, whenreferring to a set of electrodes, the set of electrodes can beconsidered as one electrode with multiple portions, or the set ofelectrodes can be considered as multiple, distinct electrodes.Additionally, for example, when referring to a plurality ofelectrochemical cells, the plurality of electrochemical cells can beconsidered as multiple, distinct electrochemical cells or as oneelectrochemical cell with multiple portions. Thus, a set of portions ora plurality of portions may include multiple portions that are eithercontinuous or discontinuous from each other. A plurality of particles ora plurality of materials can also be fabricated from multiple items thatare produced separately and are later joined together (e.g., via mixing,an adhesive, or any suitable method).

As used herein, the term “z-direction” generally means the thirddirection where longitudinal and transverse are the first and seconddirections. In other words, the z-direction refers to the depth orthickness of a feature as opposed to length and width.

As used herein, the term “about” and “approximately” generally mean plusor minus 10% of the value stated, e.g., about 250 μm would include 225μm to 275 μm, about 1,000 μm would include 900 μm to 1,100 μm.

As used herein, the term “semi-solid” refers to a material that is amixture of liquid and solid phases, for example, such as particlesuspension, colloidal suspension, emulsion, gel, or micelle.

As used herein, the terms “activated carbon network” and “networkedcarbon” relate to a general qualitative state of an electrode. Forexample, an electrode with an activated carbon network (or networkedcarbon) is such that the carbon particles within the electrode assume anindividual particle morphology and arrangement with respect to eachother that facilitates electrical contact and electrical conductivitybetween particles. Conversely, the terms “unactivated carbon network”and “unnetworked carbon” relate to an electrode wherein the carbonparticles either exist as individual particle islands or multi-particleagglomerate islands that may not be sufficiently connected to provideadequate electrical conduction through the electrode.

FIG. 1 shows a schematic illustration of a method 10 of manufacturing asemi-solid electrode in a continuous or semi-continuous manner. In someembodiments, the method 10 includes continuously dispensing a semi-solidelectrode slurry onto a current collector 11 as it passes through aconveyance system. In some embodiments, the conveyance system can beconfigured to continuously or semi-continuously transport the currentcollector past a fixed dispensing mechanism. In some embodiments, thedispensing mechanism can be adjustable and/or can move with respect tothe current collector. In some embodiments, the fixed dispensingmechanism can be a nozzle configured to dispense the semi-solidelectrode slurry at a predetermined and precise rate onto specificregions of the current collector as it is passes the fixed dispensingmechanism.

Dispensing the semi-solid slurry can generate a significant amount offorce upon the conveyance system. The force generated by dispensing thesemi-solid slurry is proportional to the loading of the semi-solidslurry (i.e., higher viscosity semi-solid slurry loading generates moreforce upon the conveyance system). In some embodiments, the force actingupon the conveyance system can be greater than 2,000 lbf, greater than2,500 lbf, greater than 3,000 lbf, or greater than 3,500 lbf. This forcecan cause mechanical deflections in the conveyance system, regardless ofhow thoroughly the system is designed to limit deflections. Thesedeflections can influence the casting gaps between the dispensingmechanism and the current collector, which impacts the thickness of theelectrode. In some embodiments, the deflection can reach 100 μm over thecourse of only 10 mm of movement of the current collector through theconveyance system. In some embodiments, an adjustable dispensingmechanism can move in such a way to counteract these deflections. Inother words, the adjustable dispensing mechanism can move up and down(i.e., along the z-axis) to compensate for the deflection caused byforce of the dispensed slurry. In some embodiments, the dispensingmechanism can move up and down (i.e., in the z-direction) along theentire width of the electrode. In some embodiments, the dispensingmechanism can move up and down on the left side of the electrode in atilted manner, such that the dispensing mechanism is lower on the leftside of the electrode than on the right side of the electrode. In someembodiments, the dispensing mechanism can move up and down on the rightside of the electrode in a tilted manner, such that the dispensingmechanism is lower on the right side of the electrode than on the leftside of the electrode.

In some embodiments, the dispensing mechanism can move to controlcasting gaps between the dispensing mechanism and the current collectorto a precision of less than 10 μm, less than 9 μm, less than 8 μm, lessthan 7 μm, less than 6 μm, less than 5 μm less than 4 μm, less than 3μm, less than 2 μm, or less than 1 μm. In some embodiments, thedispensing mechanism can move along the z-axis a distance of greaterthan about 1 μm, greater than about 5 μm, greater than about 10 μm,greater than about 20 μm, greater than about 30 μm, greater than about40 μm, greater than about 50 μm, greater than about 60 μm, greater thanabout 70 μm, greater than about 80 μm, greater than about 90 μm, orgreater than about 100 μm in order ensure the precision of the electrodethickness. The dispensing mechanism can be adjusted very rapidly inorder to match the timing of the movement of the conveyance system. Insome embodiments, the counteracting motion of the dispensing mechanismcan occur in less than 0.5 seconds, less than 0.4 seconds, less than 0.3seconds, less than 0.2 seconds, less than 0.1 seconds, less than 0.09seconds, less than 0.08 seconds, less than 0.07 seconds, less than 0.06seconds, less than 0.05 seconds, less than 0.04 seconds, less than 0.03seconds, less than 0.02 seconds, or less than 0.01 seconds. For example,the casting gap can be changed from 150 μm to 200 μm in 0.1 seconds, andthe 200 μm gap can be achieved with 1 μm precision. The casting gap canthen be subsequently changed from 200 μm to 175 μm in 0.1 seconds, andthe 175 μm gap can be achieved with 1 μm precision. In some embodiments,servo-controlled motions can control the motions of the dispensingmechanism to control casting gaps to the desired level of precision. Insome embodiments, beta gauge readings for the most recently producedelectrodes can be used to determine the movement schedule for thedispensing mechanism. In some embodiments, the dispensing mechanism cancontrol casting gaps between the dispensing mechanism and the currentcollector within the casting nozzle. In some embodiments, a blade withinthe casting nozzle can move up and down to control casting gaps betweenthe dispensing mechanism and the current collector. In some embodiments,the semi-solid electrode slurry can be configured to remain inpredetermined regions once dispensed onto the current collector.

In some embodiments, the electrodes including the semi-solid electrodeslurry described herein can decrease the volume, mass and costcontributions of inactive components with respect to active components,thereby enhancing the commercial appeal of batteries made with thesemi-solid electrodes. In some embodiments, the semi-solid electrodesdescribed herein are binderless and/or do not use binders that are usedin conventional battery manufacturing. Instead, the volume of theelectrode normally occupied by binders in conventional electrodes, cannow be occupied by: 1) electrolyte, which has the effect of decreasingtortuosity and increasing the total salt available for ion diffusion,thereby countering the salt depletion effects typical of thickconventional electrodes when used at high rate, 2) active material,which has the effect of increasing the charge capacity of the battery,or 3) conductive additive, which has the effect of increasing theelectronic conductivity of the electrode, thereby countering the highinternal impedance of thick conventional electrodes. Without wishing tobe bound by any particular theory, the reduced tortuosity and a higherelectronic conductivity of the semi-solid electrodes described herein,results in superior rate capability and charge capacity ofelectrochemical cells formed from the semi-solid electrodes.

In some embodiments, the current collector is a strip of conductivematerial that is not yet apportioned into discrete current collectors.The current collector has a length defining a longitudinal axis, and awidth that is defined as a dimension perpendicular to the longitudinalaxis. The current collector is configured to be transported though theconveyance system (i.e., the direction of travel) along its longitudinalaxis. In some embodiments, the width of the current collector can besubstantially similar to the desired width or height of the currentcollector to be used in the finished semi-solid electrode. In someembodiments, the width of the current collector can be greater thanabout 101%, 105%, 110%, 120%, 130%, 140%, 150%, 175%, 200%, 300%, 400%,or 500% of the desired width or height of the current collector to beused in the finished semi-solid electrode.

In some embodiments, the current collector has a thickness of betweenabout 0.01 μm and about 100 μm, between about 100 nm and about 100 μm,between about 1 μm and about 95 μm, between about 1 μm and about 90 μm,between about 1 μm and about 85 μm, or between about 1 μm and about 80μm, inclusive of all values and ranges therebetween. In someembodiments, the current collector has a thickness of less than about500 μm, less than about 400 μm, less than about 300 μm, less than about200 μm, less than about 100 μm, less than about 90 μm, less than about80 μm, less than about 70 μm, less than about 60 μm, less than about 50μm, less than about 45 μm, less than about 40 μm, less than about 35 μm,less than about 30 μm, less than about 25 μm, less than about 20 μm,less than about 19 μm, less than about 18 μm, less than about 17 μm,less than about 16 μm, less than about 15 μm, less than about 14 μm,less than about 13 μm, less than about 12 μm, less than about 11 μm,less than about 10 μm, less than about 9 μm, less than about 8 μm, lessthan about 7 μm, less than about 6 μm, less than about 5 μm, less thanabout 5 μm, less than about 4 μm, less than about 3 μm, less than about2 μm, less than about 1 μm, less than about 900 nm, less than about 750nm, less than about 500 nm, or less than about 100 nm, inclusive of allvalues and ranges therebetween.

The current collector is electronically conductive and can beelectrochemically inactive under the operation conditions of the cell.In some embodiments, current collector materials can include copper,aluminum, and/or titanium for the negative current collector andaluminum for the positive current collector. In some embodiments,aluminum is used as the current collector for positive electrode. Insome embodiments, copper is used as the current collector for negativeelectrode. In other embodiments, aluminum is used as the currentcollector for negative electrode.

The semi-solid electrode slurry can be electrochemically configured tobe used in the anode and/or the cathode. The semi-solid electrode slurrycan include an active material in a liquid electrolyte. In someembodiments, the active material, which may be organic or inorganic, caninclude but is not limited to lithium metal, sodium metal, lithium-metalalloys, gallium and indium alloys with or without dissolved lithium,molten transition metal chlorides, thionyl chloride, and the like, orredox polymers and organics that are liquid under the operatingconditions of the battery. Electrode formulations can include, forexample, (1) active materials (i.e., the sources and sinks of ions andelectrons), (2) carbon (or a mixture of carbons) or other material(s)having the primary, but not necessarily exclusive, function ofelectronic conduction, and (3) an electrolyte (e.g., a solvent orsolvent mixture plus salt(s)) having the primary, but not necessarilyexclusive function of ionic conduction. The electrode formulation mayoptionally include other additives having specific intended chemical,mechanical, electrical, and/or thermal functions. Electrode formulationscan include, for example, the active materials, compositions, and/orsemi-solid suspensions described in U.S. Pat. No. 8,993,159, entitled“Semi-Solid Electrodes Having High Rate Capability,” and U.S. Pat. No.9,437,864, entitled “Asymmetric Battery Having a Semi-Solid Cathode andHigh Energy Density Anode,” the entire disclosures of which are herebyincorporated by reference, respectively.

In some embodiments, the semi-solid electrode slurry can include aconductive additive, a stabilizing additive, and/or a gelling agent.Examples of semi-solid electrode slurries can be found in U.S. Pat. Nos.8,993,159, 9,178,200, 9,184,464, 9,203,092, and 9,484,569, the entiredisclosures of which are hereby incorporated herein by reference.

In some embodiments, electrodes and electrochemical cells manufactureddirectly with a semi-solid electrode slurry avoid the use ofconventional binding agents and the conventional electrode casting stepaltogether. Using a semi-solid electrode slurry can also eliminate theneed for infusing the electrode material with the electrolyte since thesemi-solid electrode slurry already includes the electrolyte. Somebenefits of this approach include, for example: (i) a simplifiedmanufacturing process with less equipment (i.e., less capitalintensive), (ii) the ability to manufacture electrodes of differentthicknesses and shapes (e.g., by changing an extrusion die slotdimension or other process conditions), (iii) processing of thicker(>100 μm) and higher areal charge capacity (mAh/cm2) electrodes, therebydecreasing the volume, mass, and cost contributions of inactivecomponents with respect to active material, and (iv) the elimination ofbinding agents, thereby reducing tortuosity and increasing ionicconductivity of the electrode.

In some embodiments, the current collector can be moved past thedispensing mechanism at a rate of greater than about 1 meter per minute,greater than about 5 meters per minute, greater than about 10 meters perminute, greater than about 15 meters per minute, greater than about 20meters per minute, greater than about 25 meters per minute, greater thanabout 30 meters per minute, greater than about 35 meters per minute,greater than about 40 meters per minute, greater than about 45 metersper minute, greater than about 50 meters per minute, greater than about55 meters per minute, greater than about 60 meters per minute, greaterthan about 65 meters per minute, greater than about 70 meters perminute, greater than about 75 meters per minute, greater than about 80meters per minute, greater than about 85 meters per minute, or greaterthan about 100 meters per minute, inclusive of all values and rangestherebetween. In some embodiments, the rate at which the currentcollector is moved past the fixed dispensing point can be between about1 meter per minute and about 100 meters per minute, between about 5meters per minute and about 80 meters per minute, between about 10meters per minute and about 70 meters per minute, between about 20meters per minute and about 60 meters per minute, and between about 30meters per minute and about 50 meters per minute, inclusive of allvalues and ranges therebetween.

In some embodiments, the current collector can be transported past thedispensing mechanism using a transmission belt, a vacuum pallet, avacuum conveyor, a belt conveyor, rollers, moving pan, a pneumaticconveyor, a hydraulic conveyor, a vibrating conveyor, a verticalconveyor, a spiral conveyor, by pulling or pushing the current collectoracross a surface having a low coefficient of friction, any othersuitable equipment or approach, or combinations thereof. In someembodiments, the current collector can be thin and highly deformable, socare should be taken not to wrinkle, fold, tear, bend, dent, orotherwise mishandle the current collector during conveyance. In someembodiments, in order to help protect the current collector from suchdamage, the current collector can be disposed onto a pouch materialbefore the semi-solid electrode slurry is disposed onto the currentcollector (e.g., step 11). In some embodiments, disposing the currentcollector onto a pouch material before the semi-solid electrode slurryis disposed onto the current collector may also help in transporting thecurrent collector past the dispensing mechanism.

The method 10 further includes separating the semi-solid electrodeslurry into discrete portions on the current collector 12. In someembodiments, the semi-solid electrode slurry can be separated into thediscrete portions on the current collector 12 by removing a portion ofthe continuously deposited semi-solid electrode slurry. In someembodiments, the semi-solid electrode slurry can be separated into thediscrete portions on the current collector 12 by making a portion of thecurrent collector temporarily unavailable to receive the depositedsemi-solid electrode slurry thereto. In some embodiments, the semi-solidelectrode slurry can be separated into the discrete portions on thecurrent collector 12 by changing the length of the current collectorwith regard to the length of continuously deposited semi-solid electrodeslurry. In some embodiments, the semi-solid electrode slurry can beseparated into the discrete portions on the current collector 12 byremoving a previously disposed obstructive material from the currentcollector once the semi-solid electrode slurry has been deposited. Insome embodiments, the discrete portions can be discrete electrodescreated by first disposing a mask material to at least a portion of thecurrent collector, disposing the semi-solid electrode slurry onto themasked current collector, and the mask material can then be removed todefine the finished electrode or electrodes.

In some embodiments, the semi-solid electrode slurry can be separatedinto discrete portions on the current collector 12 by any ofultrasonication, laser ablation, doctor blade, irradiation,high-precision cutting, or combinations thereof. In some embodiments,the semi-solid electrode slurry can be separated into discrete portionsof the current collector 12 by speeding up the current collector at somedistance past the dispensing mechanism, causing an uncoated portion ofcurrent collector to form between each discrete portion of semi-solidelectrode slurry.

In some embodiments, as discussed above, the width of the currentcollector (the dimension perpendicular to the direction of travel of thecurrent collector through the conveyance system) can be approximatelyequal to or greater than the width of the current collector to be usedin the finished electrode. In some embodiments, the width of the currentcollector can accommodate separation of the disposed semi-solidelectrode slurry into more than one electrode portion width-wise. Inother words, in some embodiments, separation of the semi-solid electrodeslurry into discrete portions on the current collector 12 can includeseparation of the semi-solid electrode slurry in two directions(parallel to the direction of travel of the current collector and alsoperpendicular to the direction of travel of the current collector).

The method 10 further includes cutting the current collector between thediscrete portions of semi-solid electrode slurry to form a finishedelectrode 13. In some embodiments, the current collector can be cut byseparating delineated sections of the current collector alongpre-perforated extent lines. In some embodiments, the current collectorcan be cut using a laser (e.g., a CO2-gas laser, high-powered diodelaser, fiber optic laser, etc.), drilling, plasma cutting, using areciprocating blade, using a punch or press, pneumatic cutting,hydraulic cutting, using other methods known to those of skill in theart, or combinations thereof.

In some embodiments, each individualized current collector with thediscrete portion of semi-solid electrode slurry disposed thereupon canbe considered the finished electrode. In some embodiments, the finishedelectrode can be disposed onto an electrically insulating material(e.g., laminate pouch material) such that the current collector directlyabuts the insulating material. In some embodiments, an adhesive can beused to retain the finished electrode on the insulating material. Insome embodiments, as described above, the current collector can bepre-disposed to the insulating material (e.g., pouch material) such thatindividualization of the current collector material also include cuttingthe insulating material to form the finished electrode.

In some embodiments, the finished electrode can include an electrode tabelectrically connected to the current collector and configured totransport electrons into or out of the electrode. In some embodiments,the electrode tab can extend beyond the current collector and/or theinsulating material. In some embodiments, the electrode tab can beelectrically coupled to the current collector before the semi-solidelectrode slurry is disposed onto the current collector. In someembodiments, the cell can include integrated electrical tabbing, whichcan obviate the need for (i) a discrete tab component (e.g., anelectrical lead), (ii) connecting dedicated tabs to current collectors,and (iii) a dedicated tab sealing operation. Instead, in someembodiments, an electrical tab or lead can be provided as an extensionof the current collector integral to the current collector. In someembodiments, the tab or lead can be defined by removal of material froma larger area of current collector material, thereby defining thecurrent collector and the tab or lead.

The method 10 optionally includes joining the finished electrode (e.g.,cathode) with a second finished electrode (e.g., anode), interposed witha separator, to form a finished electrochemical cell 14. In other words,once the finished electrode has been individualized (e.g., according tostep 13), it can be assembled into the finished electrochemical cellwith the second finished electrode exhibiting the opposite redoxreaction. In other words, the cathode and the anode can be joinedtogether with a separator disposed between.

In some embodiments, the separator can be disposed between the anode andthe cathode. In some embodiments, the separator can be joined to atleast one of the anode and the cathode with an adhesive. In someembodiments, one anode, one cathode and one separator can be stackedtogether to form a unit cell assembly. Each unit cell assembly can alsoinclude conductive tabs (also referred to as a lead) to couple theelectrodes to external circuits. Multiple unit cell assemblies are thenstacked or arrayed together to form a battery cell. In some embodiments,the number of unit cell assemblies in a battery cell may vary dependingon, for example, the desired capacity and/or thickness of the resultingbattery cell. These stacked unit cell assemblies are electrically inparallel, and respective tabs in each unit cell assembly are typicallywelded together via welding processes such as resistance welding, laserwelding, and ultrasonic welding, seam welding, electric beam welding,among others.

In some embodiments, the prepared electrochemical cell can be vacuumsealed in a prismatic pouch which can provide hermetic isolation of theelectrochemical cell materials from the environment. Thus, the pouch canserve to avoid leakage of hazardous materials such as electrolytesolvents and/or corrosive salts to the ambient environment, and canprevent water and/or oxygen infiltration into the cell. Other functionsof the pouch can include, for example, compressive packaging of theinternal layers, voltage isolation for safety and handling, andmechanical protection of the electrochemical cell assembly. In someembodiments, during vacuum pouch sealing, electrolyte can be injectedinto the stacked unit cell assembly and the unit cell assemblies and theelectrolyte can then be sealed into a pouch. In some embodiments, noelectrolyte is added during the pouch sealing step if the semi-solidelectrode slurry may contain the total desired quantity of electrolytealready.

In some embodiments, the sealed battery cell can then be subjected to aformation process, in which an initial charging operation can beperformed to create a stable solid-electrolyte-interphase (SEI) that canpassivate the electrode-electrolyte interface as well as prevent sidereactions. In some embodiments, several cycles of charging anddischarging can be carried out to ensure that the capacity of thebatteries meets the required specifications. In some embodiments, adegassing step can be performed to release gases introduced or producedduring the initial charging stage or during the electrochemicalreactions in the battery formation step. The presence of entrapped gasin the electrodes generally reduces the conductivity and density of theelectrodes, and limits the amount of active electrochemical materialsthat can be placed in a battery cell and may cause dendrite growth thatcan erode battery performance in lithium batteries. In some embodiments,dendrite formation may lead to a reduction in cycle life and a reductionin overall safety performance. In some embodiments, a reseal step can betaken to seal the battery cell again after the entrapped gas isreleased.

In some embodiments, in comparison with conventional electrochemicalcell manufacturing methods, the methods described herein can be used tomanufacture semi-solid electrodes and electrochemical cells in a shorterperiod of time. In some embodiments, the shorter time period canminimize evaporation and/or degradation of the electrolyte, reducemanufacturing cost, and reduce the necessary factory footprint for thesame output of electrochemical potential.

FIG. 2 shows a dispensing mechanism 100 that can control the length of acasting gap T of an electrode, according to an embodiment. In someembodiments, a nozzle 110 can dispense an electrode slurry 120 onto acurrent collector 130 placed on a conveyance system 140, and the castinggap T can be controlled by movement of a nozzle blade 150. In someembodiments, the casting gap T can be controlled by independent movementof the nozzle blade 150 in the z-direction with respect to the nozzle110, the current collector 130, and the conveyance system 140. In someembodiments, the casting gap T can be controlled by movement of both thenozzle 110 and the nozzle blade 150 in the z-direction with respect tothe current collector 130 and the conveyance system 140.

FIG. 3 shows a dispensing mechanism 200 that can control the length of acasting gap T between a nozzle 210 and a current collector 230 on aconveyance system 240, according to an embodiment. In some embodiments,the movement of a nozzle blade 250 in the z-direction can be controlledby set of rollers 255. The rollers 255 can be pushed in from either sideby a servo system (not shown), that can push the nozzle blade 250downward on either the left side, the right side, or throughout theentire width of the nozzle blade 250. In some embodiments, only the leftroller 255 a can be engaged to lower the nozzle blade 250 on the leftside only, such that the left side of the nozzle blade 250 is lower thanthe right side of the nozzle blade 250. In some embodiments, only theright roller 255 b can be engaged to lower the nozzle blade 250 on theright side only, such that the right side of the nozzle blade 250 islower than the left side of the nozzle blade 250. In some embodiments,both the left roller 255 a and the right roller 255 b can be engaged tolower the nozzle blade 250 along its entire width. In some embodiments,a set of springs 259 can provide a force to return the nozzle blade 250back to its original position after lowering.

FIG. 4 shows a dispensing mechanism 300 that can control the length of acasting gap T between a nozzle 310 and a current collector 330 on aconveyance system 340, according to an embodiment. In some embodiments,the movement of a nozzle blade 350 in the z-direction can be controlledby a set of cams 357. The cams 357 can be controlled by a set ofcamshafts (not shown), that can rotate to push the nozzle blade 350downward on either the left side, the right side, or throughout theentire width of the nozzle blade 350. In some embodiments, only the leftcam 357 a can be engaged to lower the nozzle blade 350 on the left sideonly, such that the left side of the nozzle blade 350 is lower than theright side of the nozzle blade 350. In some embodiments, only the rightcam 357 b can be engaged to lower the nozzle blade 350 on the right sideonly, such that the right side of the nozzle blade 350 is lower than theleft side of the nozzle blade 350. In some embodiments, both the leftcam 357 a and the right cam 357 b can be engaged to lower the nozzleblade 350 along its entire width. In some embodiments, a set of springs359 can provide a force to return the nozzle blade back to its originalposition after lowering.

Tucking Method

FIGS. 5-8 illustrate methods of manufacturing a semi-solid electrode ina continuous or semi-continuous manner. In some embodiments, the currentcollector material can be moved continuously from a current collectorfeed device, onto a conveyor, and past a dispensing mechanism. In someembodiments, the current collector material can be moved continuously byway of a conveyor system. In some embodiments, the conveyor system caninclude a series of plates that are configured to be moved paralleland/or perpendicular to the direction of travel of the conveyor. As usedherein, plates refers to a plurality of planar structures configured tobe moved with respect to the direction of travel of the conveyor systemand can also be pallets, sheets, covers, films, or other suitablestructures. In some embodiments, the conveyor system can include ashuttle conveyor, a wire belt conveyor, a belt conveyor, a perforatedconveyor, a spreading conveyor, a roller conveyor, a chain conveyor, orcombinations thereof.

In some embodiments, a vacuum belt conveyor can be used to convey thecurrent collector material through the manufacturing system. Vacuum beltconveyors typically include a perforated belt and slider bed with aconveyor frame that is sealed. In that way, air can be drawn through theholes of the frame, creating a partial vacuum. Vacuum belt conveyors canbe used to convey light and/or flat materials such that the materialsare held against the conveyor belt. Vacuum belt conveyors can be used toconvey light and/or flat materials at higher speeds, which can increasethe manufacturing rate. In some embodiments, the vacuum belt conveyorcan be used to convey light and/or flat materials in a non-horizontalorientation, for example, vertically.

In some embodiments, as shown in FIGS. 6A and 6B, a portion of thecontinuous current collector can be interposed, tucked, pleated, folded,gathered, creased, doubled over, grouped, collected, hidden, and/orotherwise excluded from deposition of electrode slurry material onto thecontinuous current collector. In other words, in some embodiments, adiscrete portion or a plurality of discrete portions of the continuouscurrent collector can be isolated and excluded from receiving theelectrode slurry material.

In some embodiments, a portion of the continuous current collector canbe moved in a direction perpendicular to the direction of travel of thecontinuous current collector. In some embodiments, after moving aportion of the current collector away from the plane of travel (e.g.,downward), the two edges of the interposed portion of the currentcollector can be moved together to fully isolate the interposed portionof the current collector.

In some embodiments, the continuous current collector can be movedacross a series of abutted plates configured to open and close duringcontinuous or semi-continuous manufacturing. In some embodiments, theplates can be configured to be approximately the size of the finishedelectrochemical cell to minimize waste of semi-solid electrode slurrymaterial. In some embodiments, the plates can be perforated or otherwiseconfigured to be able to draw vacuum across the surface of the platessuch that materials can be retained on the surface regardless of theorientation of the plates. In some embodiments, the plates can beattached to a rotary system such that plates can accommodate currentcollector at one end of a conveyor line, convey the current collectorduring deposition of the electrode material onto the current collector,and can then be diverted back to the beginning of the conveyor line. Insome embodiments, the plates can be washed or otherwise conditioned forreuse between the end of the conveyor line and the beginning of theconveyor line.

In some embodiments, the method of continuously or semi-continuouslymanufacturing a semi-solid electrode can include a first step in whichthe plates can be initially open as the continuous current collector isdisposed upon the plates. In some embodiments, as shown in FIGS. 7 and8, the continuous current collector (i.e., foil) can be fed from a reelfeeder, across one or more rollers, and onto a conveyor. In someembodiments, the continuous current collector can be substantiallysimilar to the continuous current collector described above, withrespect to FIG. 1.

In some embodiments, in a second step, a portion of the continuouscurrent collector can be disposed (e.g., interposed or tucked) betweentwo open plates by any suitable method, including but not limited to anextending rod, an air knife, a tucking wire, or any other suitablemethod. In some embodiments, the continuous current collector can beslowed, paused, or stopped in order to facilitate the disposition of theportion of the continuous current collector between the two open plates.In some embodiments, the continuous current collector can be movednonstop and disposition of the portion of the continuous currentcollector between the two open plates can be carried out on-the-fly. Insome embodiments, a flying tucking device can be used, which can beconfigured to move at substantially the same speed as the continuouscurrent collector while causing the interposition of the portion of thecontinuous current collector between the plates. In some embodiments, afixed tucking device can be used that is configured to tuck the portionof the continuous current collector between the plates as the continuouscurrent collector moves past the fixed tucking device. In someembodiments, a computer vision system can be configured to monitor thetucking step and control precisely the tucking device, the movement ofthe plates, and the timing of the tucking and untucking. In someembodiments, the computer vision system can be a closed loop computervision system including a video camera, a processor, a memory, a powersupply, and a computer-readable media configured to provide processingfeedback to an automated manufacturing system.

In some embodiments, in a third step, the two open plates can be movedinto a closed configuration where the two plates substantially abut oneanother and the interposed portion of the continuous current collectoris retained between the two plates. In some embodiments, the closure ofthe plates can hold the interposed portion of the continuous currentcollector between the plates. In some embodiments, plates can have asecuring edge such that the securing edge of one plate can directly abutthe securing edge of the adjacent plate to frictionally engage thecurrent collector. In some embodiments, the securing edge can include amaterial that deforms to some extent when the plates close, which canincrease how securely the portion of the continuous current collector isheld between the plates in the third and fourth steps.

In some embodiments, in a fourth step, the semi-solid electrode slurrycan be disposed onto the continuous current collector by a dispensingmechanism. As shown in FIG. 6A, the disposed semi-solid electrode slurrycan be disposed onto the continuous current collector without beingdisposed onto the interposed portion of the continuous currentcollector. In some embodiments, the deformable securing edge may helpreduce or eliminate the loss of semi-solid electrode slurry onto theportion of the continuous current collector interposed between the twoplates.

In some embodiments, the dispensing mechanism can be a nozzle configuredto dispense the semi-solid electrode slurry at a predetermined andprecise rate onto specific regions of the current collector as it ispasses the dispensing mechanism. In some embodiments, the semi-solidelectrode slurry can be configured to remain in predetermined regionsonce dispensed onto the current collector.

In some embodiments, as shown in FIG. 7, the semi-solid electrode slurrycan be disposed continuously or semi-continuously onto the currentcollector using parallel vertical tape casting/hybrid tape casting(VTC/HTC) stations including parallel slurry cartridges. In someembodiments, as shown in FIG. 8, the semi-solid electrode slurry can bedisposed continuously or semi-continuously onto the current collectorusing a casting station.

In some embodiments, as shown in FIG. 8, the continuous currentcollector can be cut to obtain a current collector having the dimensionsof the desired current collector in the finished electrode. In someembodiments, the individual current collectors can be picked up from theweb reel and placed onto the conveyor system described above with regardto FIG. 5. In some embodiments, the individual current collectors can beplaced directly onto the plates, the plates configured to open and closeto eliminate and then create a distance between each current collector.In some embodiments, the individual current collectors can be picked upfrom the web reel and placed onto a pouch material, the pouch materialconfigured to become at least some part of the insulated outer coatingof the finished electrochemical cell. In some embodiments, the pouchmaterial can be a continuous pouch material, and can be fed from aroller onto the plates. Without wishing to be bound by any particulartheory, it may make it easier to move and handle the thin currentcollectors when they are disposed to (e.g., coupled to) the pouchmaterial rather than being handled individually. In some embodiments,the pouch material with the individual current collectors disposed tothe surface thereof can be fed onto a conveyor including plates, theplates being in the open configuration. In some embodiments, the platescan be positioned and configured such that only pouch material (nocurrent collector material) extends beyond the extent of a plate. Insome embodiments, a tucking device (e.g., the flying tucker describedherein) can be used to dispose a portion of the pouch material betweentwo plates, the plates configured to be moved into the closedconfiguration to secure the portion of the pouch material therebetween.In some embodiments, when the portion of the pouch material is disposedbetween two plates and isolated by closing the plates, the only surfaceof the pouch material remaining on the plates is pouch material with thecurrent collector coupled to the pouch material. In other words, theindividual current collectors are coupled to the pouch material with aportion of current collector material between, the portion of currentcollector is interposed between the plates, and the remaining surface isa continuous surface of current collector. In some embodiments, thesemi-solid electrode slurry can then be disposed onto the currentcollector in a continuous or semi-continuous manner and the plates canbe opened to separate the individual finished electrodes.

In some embodiments, in an optional fifth step, the dispensed semi-solidelectrode slurry can be spread out to a particular thickness across thecontinuous current collector, for example, using a doctor blade, aroller, a calendering process, a moving press, or combinations thereof.In some embodiments, the semi-solid electrode slurry can be depositedonto a subset of the current collector (e.g., in the middle of thecontinuous current collector). In some embodiments, the optional fifthstep can be carried out at an elevated temperature. In some embodiments,a plastic film (e.g., polyethylene terephthalate film) can be disposedonto the semi-solid electrode slurry before the calendering step suchthat the semi-solid electrode slurry remains substantially disposed onthe current collector rather than sticking to a calendering roller orother calendaring device.

In some embodiments, in a sixth step, the plates can be opened to exposethe interposed portion of the continuous current collector and separatethe discrete portions of semi-solid electrode slurry on the continuouscurrent collector. In some embodiments, the plates can be opened bymanually forcing the plates opening and/or by speeding up the continuouscurrent collector. In some embodiments, as shown in FIG. 6B, thediscrete portions of semi-solid electrode slurry can be configured tohave well structured (i.e., clean or straight) lines on two or moresides of the discrete portion of the semi-solid electrode slurry. Insome embodiments, each discrete portion of the semi-solid electrodeslurry on the current collector can be considered an electrode for anelectrochemical cell.

In some embodiments, before opening the plates to expose the discreteportions of the semi-solid electrode slurry, a scoring device can beused to score the semi-solid electrode slurry. In some embodiments, thescoring device can be used to score the semi-solid electrode slurry at alocation corresponding generally to the interface between the plates toaid in clean separation of the semi-solid electrode slurry when theplates open. In some embodiments, the scoring mechanism can include atensioned wire. In some embodiments, the tensioned wire can be heated orvibrated to aid in scoring of the semi-solid electrode slurry. In someembodiments, the scoring mechanism can include a moving blade. In someembodiments, the scoring mechanism can include a directed fluid or airjet. In some embodiments, the scoring device can include an ultrasonicknife configured to separate the semi-solid electrode slurry intodiscrete portions. In some embodiments, the action of opening the platescan separate the discrete portions of the semi-solid electrode slurrywithout the need for a scoring device. In some embodiments, the platescan be moved into the open configuration by moving one of the platesaway from the other, the other plate remaining in a fixed relativeposition. In some embodiments, the plates can be moved into the openconfiguration by moving both plates away from the other concurrently. Insome embodiments, the plates can be moved into the open configuration bymoving first one interfacing corner of the plate away from thecorresponding corner of the opposite plate and then subsequently movingthe other interfacing corner of the plate away from the secondcorresponding corner of the opposite plate. In other words, plates canbe rotated away from adjacent plates if doing so is helpful for creatinga clean break of the semi-solid electrode slurry.

In some embodiments, in a seventh step, the current collector can be cutperpendicular to the direction of travel of the current collectorbetween each discrete portion of semi-solid electrode slurry to formindividual electrodes. In some embodiments, the current collector can becut using a laser (e.g., a CO2-gas laser, high-powered diode laser,fiber optic laser, etc.), drilling, plasma cutting, using areciprocating blade, using a punch or press, pneumatic cutting,hydraulic cutting, using other methods known to those of skill in theart, or combinations thereof. In some embodiments, as shown in FIG. 8,individual electrodes can be picked up from the conveyor (e.g., using arobotic arm) and placed onto a different conveyor. In some embodiments,if the finished electrode is not already coupled to the pouch material,the individual electrodes can be coupled to the pouch material in thisstep. In some embodiments, the individual electrode can optionally becalendered to reduce the thickness of the semi-solid electrode slurry onthe current collector and/or to reduce defects. In some embodiments, abeta gauge such as a moving web thickness and/or weight measurementsystem can be used to ensure proper and consistent z-directionalthickness of the semi-solid electrode slurry on the current collector.In some embodiments, a video camera and computer processor can be usedto visually inspect the finished electrodes and discard any defectiveelectrodes, e.g., using a computer vision program.

This design provides for an electrochemical cell to adopt various formfactors, which allows an electrochemical cell to be constructed intospecialized shapes and sizes for particular applications. In someembodiments, the shape and design of cathode and anode may determinethat of the resulting battery. In some embodiments, the use of varyingelectrode material, e.g., semi-solid constituents, separator, andcompartment volumes determine the battery's power and energycapabilities.

In some embodiments, in an optional eighth step, the individualizedelectrode (e.g., cathode) can be paired with the separator and a secondindividualized electrode (e.g., anode) to form the electrochemical cell.In some embodiments, the formed electrochemical cell can be sealed on atleast one edge within a pouch material. In some embodiments, the formedelectrochemical cell can be sealed on at least two edges within a pouchmaterial. In some embodiments, the formed electrochemical cell can besealed on at least three edges within a pouch material. In someembodiments, the formed electrochemical cell can be sealed on at leastfour edges within a pouch material. In some embodiments, the semi-solidelectrode slurry can include less of an electrolyte than the quantity ofelectrolyte that the finished electrode will include when finallyformed. In some embodiments, at least a portion of the electrolyte canbe added during or after the eighth step. In some embodiments, aftersealing the electrochemical cell into the pouch material, theelectrochemical cell can be cycled through one or more charge/dischargecycles. In some embodiments, after the initial cycling of theelectrochemical cell, the pouch material can be punctured in order torelease any gases formed during initial cycling. In some embodiments,after degassing of the sealed electrochemical cell pouch, the pouch canbe resealed along the fourth edge using a heat sealer.

Tucking Plus Masking Material

In some embodiments, a continuous or semi-continuous method formanufacturing the semi-solid electrode can include a combination of oneof the methods described above with regard to FIGS. 5-8 and anadditional step of physically disposing a portion of the currentcollector between two plates to define at least one edge of the finishedelectrode. In some embodiments, such a hybrid method can include a firststep in which the plates can be initially open as the continuous currentcollector is disposed onto the plates. In some embodiments, thecontinuous current collector can be fed from a reel feeder, across oneor more rollers, and onto a conveyor. In some embodiments, thecontinuous current collector can be substantially similar to thecontinuous current collector described above, with respect to FIG. 1.

In some embodiments, in a first step, a portion of the continuouscurrent collector can be disposed (e.g., interposed or tucked) betweentwo open plates, for instance using an air knife.

In some embodiments, in a second step, the two open plates can be movedinto a closed configuration where the two plates substantially abut oneanother and the interposed portion of the continuous current collectoris retained between the two plates. In some embodiments, the closure ofthe plates can hold the interposed portion of the continuous currentcollector between the plates.

In some embodiments, in a third step, a masking material can be disposedonto the exposed portion of the continuous current collector to protectat least a portion of the current collector from receiving a coating ofthe semi-solid electrode slurry and to define at least one edge of thecurrent collector. In some embodiments, the edge of the currentcollector can be defined by limiting the extents of where the semi-solidelectrode slurry can be coated. In some embodiments, the maskingmaterial can be initially stored in a rolled state and can be fed ontothe current collector by a mask material dispensing system.

In some embodiments, the masking material can be applied in a directionparallel to the direction of travel of the continuous current collector.In some embodiments, the masking material can be applied before theportion of the current collector is interposed between the two plates.In other words, the masking material can be applied to the currentcollector and then a portion of both the current collector and themasking material can be interposed between the two plates. While theinterposition of the already masked current collector has the potentialto cause damage to or misalignment of the masking material, it can alsosecure the masking material during deposition of the semi-solidelectrode slurry onto the masked, interposed current collector.

In some embodiments, the masking material can be applied to thecontinuous current collector after the continuous current collector isunspooled from a feed reel or similar device but before the semi-solidelectrode slurry is disposed onto the current collector. In someembodiments, the masking material can be applied to the continuouscurrent collector before it is spooled onto the feed reel or similardevice.

In some embodiments, in a fourth step, the semi-solid electrode slurrycan be disposed onto the masked, partially interposed continuous currentcollector by a dispensing mechanism. In some embodiments, the disposedsemi-solid electrode slurry can be disposed onto the continuous currentcollector without being disposed onto the interposed portion of thecontinuous current collector. In some embodiments, some of thesemi-solid electrode slurry material disposed onto the current collectormay also be disposed onto the masking material. In some embodiments, theabutment of the plates may help reduce or eliminate the loss ofsemi-solid electrode slurry onto the portion of the continuous currentcollector interposed between the two plates.

In some embodiments, in a fifth step, the masking material can beremoved from the current collector surface before moving the two platesinto the open configuration. The removed masking material can beconnected to a mask material recovery system. In some embodiments, themask material recovery system can include a subsystem for cleaning anyaccumulated semi-solid electrode slurry off the masking material. Insome embodiments, the masking material can be removed from the currentcollector surface after moving the two plates into the openconfiguration. In some embodiments, the masking material can be a closedloop system such that after the masking material is used and cleaned, itcan be reused in the same manufacturing process. In other words, themasking material can be cleaned and returned to the beginning of theelectrode manufacturing process to be applied to the current collector.In some embodiments, a more durable masking material can be used inorder for the life of the masking material to make its usecost-effective.

In some embodiments, in a sixth step, the plates can be opened to exposethe interposed portion of the continuous current collector. In someembodiments, opening the plates can also separate the discrete portionsof semi-solid electrode slurry on the continuous current collector. Insome embodiments, the plates can be opened by mechanical action on theplates. In some embodiments, the plates can be opened, at least in part,by speeding up the conveyance speed of the continuous current collector.In some embodiments, as shown in FIG. 6B, the discrete portions ofsemi-solid electrode slurry can be configured to have well-structured(i.e., clean or straight) lines on two or more sides of the discreteportion of the semi-solid electrode slurry. In some embodiments, eachdiscrete portion of the semi-solid electrode slurry on the currentcollector can be considered an electrode for an electrochemical cell.

Continuous Method

FIGS. 9-11 illustrate methods of manufacturing a semi-solid electrode ina continuous manner by covering or otherwise protecting a portion of thecontinuous current collector from being coated by the semi-solidelectrode slurry. In some embodiments, the continuous current collectorcan be protected by the prior application of masking material. In someembodiments, the masking material can be applied onto the continuouscurrent collector before it is loaded onto the current collector feeddevice configured to feed the current collector to the conveyor, e.g., areel feeder.

In some embodiments, the masking materials can be printed onto thecurrent collector such that it is permanently disposed to the currentcollector. In some embodiments, the masking material can be printed ontothe current collector during the manufacture of the current collector.

In some embodiments, the masking material can be applied to thecontinuous current collector after it is unspooled from the currentcollector feed device but before the semi-solid electrode slurry isdisposed to the masked current collector.

In some embodiments, the masking material can include any suitablematerial configured to removably adhere to the current collector at therange of temperatures and conditions experienced during manufacturing.In some embodiments, the masking material can be made from a polymer, across-linking agent, a thermoplastic polymer, polyimides, a nonwovensynthetic material, an extruded thermoforming material, a paper, ametal, a natural fiber, or combinations thereof. In some embodiments,the masking material can include an adhesive, such as a rubber-basedadhesive, an acrylic-based adhesive, or a silicone-based adhesive.

In some embodiments, the masking material can be applied in a directionparallel and/or perpendicular to the direction of travel of thecontinuous current collector. In some embodiments, the masking materialapplied in the perpendicular direction can be applied separately fromthe masking material applied in the parallel direction. In someembodiments, the masking material can include a web structure such thatthe masking material in both the parallel direction and theperpendicular direction are included in one material and applied at thesame time.

In some embodiments, at least partially because the plates do not needto be moved between the open and closed configuration, thismanufacturing process can be substantially fully continuous. In someembodiments, the conveyor system can be used to move the masked currentcollector past the dispensing mechanism, e.g., slurry casting station.Without wishing to be bound by any particular theory, because thecurrent collector is at least partially masked, the slurry casting ratecan be increased substantially, at least to a point, without a trade-offof less precise, crumbling electrode edges.

In some embodiments, the semi-solid electrode slurry can be applied ontothe masked current collector using an engineered nozzle configured toapportion the slurry precisely onto the current collector. In someembodiments, the deposition of semi-solid electrode slurry here can besubstantially similar to methods described above with respect to FIG. 1.

In some embodiments, once the semi-solid electrode slurry is disposedonto the masked current collector, the manufacturing process can includean optional slurry-spreading step. In some embodiments, slurry spreadingcan be carried out using a roller or a series of rollers. In someembodiments, a doctor blade or other similar device can be used toremove excess slurry material from the masked current collector.

In some embodiments, once the slurry has been spread out substantiallyevenly on the current collector, the surface velocity of the currentcollector along the conveyor can be increased to create a slight gapbetween the formed electrodes. In some embodiments, the gap createdbetween formed electrodes can be between about 100 μm and about 15 mm,between about 250 μm and about 10 mm, between about 500 μm and about 9mm, between about 750 μm and about 8 mm, between about 1 mm and about 7mm, between about 2 mm and about 6 mm, or between about 3 mm and about 5mm, inclusive of all values and ranges therebetween. In someembodiments, the gap created between formed electrodes can be greaterthan about 100 μm, 250 μm, 500 μm, 750 μm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm,6 mm, 7 mm, 8 mm, 9 mm, 10 mm, or 15 mm, inclusive of all values andranges therebetween.

In some embodiments, the formed electrodes can be calendered by passingthe formed electrodes between two or more rollers to compress andoptionally heat the formed electrodes. In some embodiments, the formedelectrodes can be calendered to a particular density, for examplegreater than about 1 g/cm3, 1.5 g/cm3, 1.75 g/cm3, 2 g/cm3, 2.25 g/cm3,2.5 g/cm3, 2.75 g/cm3, 3 g/cm3, 3.25 g/cm3, 3.5 g/cm3, 3.75 g/cm3, orgreater than about 4 g/cm3, inclusive of all values and rangestherebetween. Without wishing to be bound by any particular theory,among other outcomes, calendering of the electrodes may result in adesired porosity reduction (increase in energy density), ahomogenization of the z-direction thickness, and/or a decrease incontact resistance at the current collector-electrode interface.

In some embodiments, the calendering process can result in a semi-solidelectrode having a porosity of less than about 99% of the porosity ofthe non-calendered semi-solid electrode, less than about 95%, 90%, 85%,80%, 75%, 70%, 65%, 60%, 55%, or less than about 50%, inclusive of allvalues and ranges therebetween. In some embodiments, reduction inporosity to less than about 60% of the non-calendered semi-solidelectrode may result in tears or other defects to the semi-solidelectrode and/or current collector.

In some embodiments, the calendering process can result in a semi-solidelectrode having a raw porosity of less than about 50%, 45%, 40%, 35%,30%, 25%, 20%, 19%, 18%, 17%, 16%, 15%, 14%, 13%, 12%, 11%, 10%, 9%, 8%,7%, 6%, or less than about 5%, inclusive of all values and rangestherebetween.

In some embodiments, after calendering, the finished electrode includingthe current collector and the semi-solid electrode slurry can have az-direction thickness of less than about 2,000 μm, less than about 1,500μm, less than about 1,000 μm, less than about 750 μm, less than about500 μm, less than about 250 μm, less than about 200 μm, less than about150 μm, less than about 100 μm, less than about 75 μm, less than about50 μm, or less than about 25 μm, inclusive of all values and rangestherebetween. In some embodiments, the finished electrode including thecurrent collector and the semi-solid electrode slurry can have az-direction thickness of between about 25 μm and about 2,000 μm, about25 μm and about 1,500 μm, about 50 μm and about 1,000 μm, about 75 μmand about 750 μm, or about 100 μm and about 500 μm, inclusive of allvalues and ranges therebetween.

In some embodiments, after the formed electrodes have been optionallycalendered, the mask material can be removed from the continuous currentcollector. In some embodiments, the mask material can be connected to amask material recovery system, the mask material recovery systemconfigured to force the removal of the masking material from thecontinuous current collector. In some embodiments, the removal of themasking material from the continuous current collector can be carriedout in a controlled manner such that the masking material does notremove any of the semi-solid electrode slurry from the formed electrode.In some embodiments, the mask material recovery system can include asubsystem for cleaning any accumulated semi-solid electrode slurry offthe masking material.

In some embodiments, the removal of the masking material can create agap between each formed electrode. In some embodiments, the gap createdbetween each formed electrode may be sufficient to allow for cleanseparation of each discrete formed electrode on the continuous currentcollector. In some embodiments, the gap created between each formedelectrode may be sufficient to allow for cutting of the continuouscurrent collector to form individual electrodes.

In some embodiments, the current collector can be cut perpendicular tothe direction of travel of the current collector between each discreteportion of semi-solid electrode slurry to form individual electrodes. Insome embodiments, the current collector can be cut using a laser (e.g.,a CO2-gas laser, high-powered diode laser, fiber optic laser, etc.),drilling, plasma cutting, using a reciprocating blade, using a punch orpress, pneumatic cutting, hydraulic cutting, using other methods knownto those of skill in the art, or combinations thereof. In someembodiments, as shown in FIG. 8, individual electrodes can be picked upfrom the conveyor (e.g., using a robotic arm) and placed onto adifferent conveyor. In some embodiments, if the gap created between eachformed electrode is insufficient after cutting the continuous currentcollector, the speed of the conveyor can be increased past a particularpoint in order to create more space between adjacent formed electrodes.

In some embodiments, if the finished electrode is not already coupled tothe pouch material, the individual electrodes can be coupled to thepouch material in this step. In some embodiments, the individualelectrodes can be coupled to the pouch material by heating at least aportion of the pouch material to fuse the pouch material to the currentcollector. In some embodiments, an adhesive can be used to adhere thepouch material to the current collector.

In some embodiments, the individual electrode can optionally becalendered to reduce the thickness of the semi-solid electrode slurry onthe current collector and/or to reduce defects. In some embodiments, abeta gauge such as a moving web thickness and/or weight measurementsystem can be used to ensure proper and consistent z-directionalthickness of the semi-solid electrode slurry on the current collector.In some embodiments, a video camera and computer processor can be usedto visually inspect the finished electrodes and discard any defectiveelectrodes, e.g., using a computer vision program.

In some embodiments, e.g., as shown in FIG. 11, the semi-solid electrodeslurry can be disposed onto the current collector on a roll castingsystem. In some embodiments, the roll casting system can include avacuum pallet or vacuum conveyor system configured to convey the currentcollector through the manufacturing system. In some embodiments, theanode can be manufactured in an anode conveyor system and the cathodecan be manufactured in a cathode conveyor system. In some embodiments,the anode conveyor system and the conveyor system can be positionedopposite each other so that the conveyors deliver finished anodes nearbyfinished cathodes for easy electrochemical cell assembly. In someembodiments, a separator roll feeder can deliver a constant orintermittent supply of a separator material between each anode and thecorresponding cathode. In some embodiments, the separator can beinterposed between the cathode and the anode after the mask material isremoved and before or after the finished electrodes are formed bycutting the current collectors.

In some embodiments, once the mask material is removed, the conveyorsystems can be configured to convey the current collector past a betagauge to determine the thickness of the semi-solid electrode slurry onthe current collector. In some embodiments, if the finished electrode isthicker than desired, the electrode can be calendered (before or afterthe mask material is removed) to reduce the thickness and/or densify thesemi-solid electrode material and/or remove electrolyte.

In some embodiments, the roll casting system can be configured tocontinuously form cathodes and continuously form electrodes,continuously interpose a separator therebetween. In some embodiments,the roll casting system can continuously form finished electrodes bysealing the discrete portions of the semi-solid electrode materialsbetween portions of a pouch material and cutting the pouch material toform the individual pouch cells.

Endo Frame

In some embodiments, the continuous or semi-continuous process ofmanufacturing a semi-solid electrode can include the use of an endoframe structure. In some embodiments, instead of or in addition tomasking material, as described above, the endo frame structure can bedisposed onto the current collector before disposing the semi-solidelectrode slurry onto the current collector. In some embodiments, theendo frame can hold the current collector in place. In some embodiments,the endo frame can have at least some z-directional thickness such thatthe endo frame at least partially defines a cavity into which thesemi-solid electrode slurry can be disposed and retained on the surfaceof the current collector.

In some embodiments, the endo frame can at least partially define thesurface area of the finished electrode (e.g., as the interior extents ofthe endo frame). In some embodiments, the endo frame can at leastpartially define the thickness of the semi-solid electrode slurry on thecurrent collector based upon the z-directional height of the endo frame.In some embodiments, the semi-solid electrode slurry can be smoothed orspread along the surface of the exposed portion of the currentcollector. In some embodiments, a blade (also referred to herein as“doctor blade”) or other straight edged instrument can be used to spreadthe semi-solid electrode slurry. In some embodiments, the blade and/orthe endo frame can be operably coupled to a vibration source to vibratethe blade or the endo frame during semi-solid electrode slurrydeposition or smoothing. The vibration may facilitate dispersion of thesemi-solid electrode slurry material during or after the slurrydeposition step.

In some embodiments, an instrument, such as for example, an optical orany analytical tool using any of non-contact measurement techniques,including optical or laser interferometry, ellipsometry or optical orlaser scanning probe to inspect surface morphology and optionallymeasure surface uniformity (e.g., thickness) of the spread semi-solidelectrode slurry. In some embodiments, the non-contact instrument can bedeployed in situ as the blade spreads the semi-solid electrode slurry.

In some embodiments, after the semi-solid electrode slurry is spread,the endo frame can be removed leaving only the portion of the semi-solidelectrode slurry that has been spread onto the exposed portion of thecurrent collector. Alternatively, in some embodiments, after thesemi-solid electrode slurry is spread, the endo frame can remain inplace and a separator can be placed on the finished electrode such thatthe separator, the current collector, and the endo frame each partiallydefine an electroactive zone and contain the semi-solid electrode slurrywithin the electroactive zone.

In some embodiments, masking material can be used in addition to theendo frame in order to prevent contamination of the uncoated portion ofthe current collector and/or any exposed portions of the pouch material.In some embodiments, the endo frame can be disposed onto the currentcollector initially, and masking material can be applied subsequently toprotect and/or define one, two, three or four of the edges of thefinished electrode. In some embodiments, the masking may extend to orbeyond the edge of the current collector material. In some embodiments,the masking material and the endo frame may be initially integral piecesof a single disposed material, the single disposed material configuredsuch that the masking can be removed while the endo frame remainsdisposed onto the current collector. In some embodiments, the singledisposed material including the endo frame and the masking material canbe substantially fully removed from the current collector after thesemi-solid electrode slurry is disposed onto the current collector.

In some embodiments, the endo frame can extend out to the edge of thecurrent collector material such that semi-solid electrode slurry can bedisposed more rapidly and less judiciously onto the continuous currentcollector. Likewise, in some embodiments, each endo frame can bepositioned and configured to directly and securely abut at least oneother endo frame such that semi-solid electrode slurry cannot bedisposed the continuous current collector or pouch material between thetwo or more endo frames. In some embodiments, after the semi-solidelectrode slurry has been disposed to the current collector, a vibratoryor other suitable method can be used to remove any semi-solid electrodeslurry that has built up on top of the endo frame structure.

In some embodiments, the endo frame and/or masking material can beconfigured such that the endo frame and/or masking material naturallyrepels the semi-solid electrode slurry to some extent, based onchemistry, electrochemistry, physical structure, or othercharacteristics. In some embodiments, the endo frame and/or maskingmaterial can be made from a material that creates a small contact anglewith respect to the semi-solid electrode slurry. In some embodiments,the endo frame and/or masking material used when manufacturing the anodecan be different from the endo frame and/or masking material used whenmanufacturing the cathode due to chemical differences between the anodesemi-solid electrode slurry and the cathode semi-solid electrode slurry.

Continuous with Doctor Blade

FIGS. 12A-12C illustrate various steps in a process of manufacturing anelectrochemical cell having at least one of the anode and cathodeincluding a semi-solid electrode slurry. As shown in FIG. 12A, at step1, a masking material can be placed over a portion of an electricallyconductive material that can be used as the current collector for theelectrochemical cell. In some embodiments, the masking material can bedisposed to the conductive material such that only the exposed portionof the conductive material visible through the masking is available fordeposition of the semi-solid electrode slurry. In some embodiments, theconductive material can include a protruding piece of conductivematerial that can be a power connection tab.

As shown in FIG. 12B, at step 2, the semi-solid electrode slurry can beplaced on the exposed portion of the conductive material. At steps 3 and4, the electrode can be smoothed or spread along the surface of theexposed portion of the second layer. For example, a blade or straightedged instrument can be used to spread the electrode. At step 5, themasking can be removed, leaving only the portion of the electrode thathas been spread onto the exposed portion of the conductive material. Asshown in FIG. 12C, at step 6, a separator can be placed on a portion ofthe current collector such that the separator is covering the electrode.At step 7, the completed semi-solid electrode and separator of step 6can be joined with another electrode. For example, the electrode of step6 can be a cathode electrode and the other electrode can include ananode electrode. At step 8, a vacuum and heat seal process can beperformed to seal the two laminate sheets together to form the finishedcell as shown at step 9.

In some embodiments, after semi-solid electrode slurry deposition, thefinished cathodes and anodes can be stacked with a separator interposed.In some embodiments, the separator is first disposed to the pouchmaterial and a cathode can be stacked onto the separator, then theseparator can be folded over the cathode and an anode can be stackedonto the separator and the separator can be folded back across theanode. In some embodiments, this process of folding the separator backand forth and alternatively stacking anode and cathode can be carriedout until the appropriate number of anodes and cathodes are assembledaccordingly. In some embodiments, the cathode and anode can be arrangedaccording to a transverse or longitudinal plane and sealed intoformation by any of the heat sealing methods described herein. In someembodiments, the resulting assembly can be folded in a zig-zag patternwith the separator to form the finished electrochemical cell. While theuse of either stacking or zig-zag folding have been described withrespect to a continuous manufacturing processing using maskingmaterials, either of the methods for handling the finished electrodes,or any other suitable method, can be used with any of the methods andsystems described herein.

While various embodiments have been described above, it should beunderstood that they have been presented by way of example only, and notlimitation. Where schematics and/or embodiments described above indicatecertain components arranged in certain orientations or positions, thearrangement of components may be modified. While the embodiments havebeen particularly shown and described, it will be understood thatvarious changes in form and details may be made. Although variousembodiments have been described as having particular features and/orcombinations of components, other embodiments are possible having acombination of any features and/or components from any of embodimentsdescribed herein.

The specific configurations of the various components can also bevaried. For example, the size and specific shape of the variouscomponents can be different from the embodiments shown, while stillproviding the functions as described herein. More specifically, the sizeand shape of the various components can be specifically selected for adesired or intended usage. Thus, it should be understood that the size,shape, and/or arrangement of the embodiments and/or components thereofcan be adapted for a given use unless the context explicitly statesotherwise.

Where methods and/or events described above indicate certain eventsand/or procedures occurring in certain order, the ordering of certainevents and/or procedures may be modified. Additionally, certain eventsand/or procedures may be performed concurrently in a parallel processwhen possible, as well as performed sequentially as described above.

The invention claimed is:
 1. A method, comprising: continuouslydispensing a semi-solid electrode slurry onto a first portion and asecond portion of a current collector material; separating thesemi-solid electrode slurry into discrete portions by moving the firstportion of current collector material relative to the second portion ofcurrent collector material thereby exposing an uncoated portion ofcurrent collector material; and cutting the uncoated portion of currentcollector material to form a plurality of discrete electrodes.
 2. Themethod of claim 1, further comprising: adjoining one of the discreteelectrodes with a second electrode interposed by a separator to form afinished electrochemical cell.
 3. The method of claim 1, wherein thesemi-solid electrode slurry is binderless.
 4. The method of claim 1,wherein the semi-solid electrode slurry is dispensed via a fixeddispensing mechanism.
 5. The method of claim 4, wherein the currentcollector material is moved past the fixed dispensing mechanism at arate of greater than about 1 meter per minute.
 6. The method of claim 4,wherein the fixed dispensing mechanism includes a nozzle configured todispense the semi-solid electrode slurry onto a plurality of regions ofthe current collector material at a predetermined rate as the currentcollector material passes the fixed dispensing mechanism.
 7. The methodof claim 1, wherein the semi-solid electrode slurry is dispensed via anadjustable dispensing mechanism.
 8. The method of claim 7, wherein theadjustable dispensing mechanism is a nozzle configured to move along thez-axis.
 9. The method of claim 8, wherein the nozzle controls castinggaps to a precision of less than 1 μm.
 10. A method, comprising:continuously dispensing a semi-solid electrode slurry onto a firstportion and a second portion of a current collector material while athird portion is isolated from the dispensing; separating the semi-solidelectrode slurry into discrete portions by moving the first portion ofcurrent collector material relative to the second portion of currentcollector material thereby exposing the third portion of currentcollector material; and cutting the third portion of current collectormaterial to form a plurality of discrete electrodes.
 11. The method ofclaim 10, further comprising: adjoining one of the discrete electrodeswith a second electrode interposed by a separator to form a finishedelectrochemical cell.
 12. The method of claim 10, wherein the semi-solidelectrode slurry is binderless.
 13. The method of claim 10, wherein thesemi-solid electrode slurry is dispensed via a fixed dispensingmechanism.
 14. The method of claim 13, wherein the current collectormaterial is moved past the fixed dispensing mechanism at a rate ofgreater than about 1 meter per minute.
 15. The method of claim 13,wherein the fixed dispensing mechanism includes a nozzle configured todispense the semi-solid electrode slurry onto a plurality of regions ofthe current collector material at a predetermined rate as the currentcollector material passes the fixed dispensing mechanism.
 16. The methodof claim 10, wherein the semi-solid electrode slurry is dispensed via anadjustable dispensing mechanism.
 17. The method of claim 16, wherein theadjustable dispensing mechanism is a nozzle configured to move along thez-axis.
 18. The method of claim 17, wherein the nozzle controls castinggaps to a precision of less than 1 μm.